1. Technical Field
The present invention relates to a communications device and method and, more specifically, to a transmission device, a reception device, a transfer device, a transmission method, a reception method, and a transfer method using radio carrier waves and optical carrier waves.
2. Related Art
Light, infrared ray to be precise, has been used for communications between transmission and reception devices of previous type, e.g., between a mobile phone and a car navigation system as described in Patent Document 1 (JP-A-2004-294310) Between a device disposed at a place for maintenance and a server device, communications has been performed by cable, by radio, by infrared ray, or others as described in Patent Document 2 (JP-A-2006-217015), and between a mobile phone and any other information equipment, communications has been performed using a visible light source, e.g., backlight such as liquid crystal panel, as described in Patent Document 3 (JP-A-2006-319408).
The issue here is that the above transmission and reception devices of previous type perform communications only by either light or radio. In this case, if any trouble occurs on an optical transmission path during communications by light, this results in a difficulty or an impossibility to continue the communications by light. Similarly, if any trouble occurs on a radio transmission path during communications by radio, this results in a difficulty or an impossibility to continue the communications by radio.